Hydraulic fracturing is generally applied after a borehole is drilled and a wellbore formed. Hydraulic fracturing is a well-stimulation technique in which rock is fractured by a pressurized liquid. Hydraulic fracturing employs fluid and material to generate fractures in a geological formation in order to stimulate production from oil and gas wells. The process can involve the pressurized injection of fracturing fluid into a wellbore to generate cracks in the deep-rock formations through which natural gas, petroleum, and brine will flow more freely. Hydraulic fracturing may increase the flow of oil and gas from a well. The fracturing typically generates paths that increase the rate at which production fluids can be produced from the reservoir formations. The amount of increased production may be related to the amount of fracturing.
Hydraulic fracturing may allow for the recovery of oil and natural gas from formations (for example, shale) that geologists once believed were impossible to produce. Hydraulic fracturing may be employed in tight sandstone, shale, and coal beds to increase crude oil or gas flow to a well from petroleum-bearing rock formations. Hydraulic fracturing can be applied for vertical, horizontal, or deviated wellbores. A beneficial application may be horizontal wellbores in unconventional formations having hydrocarbons such as natural gas and crude oil. Proppants may be employed to maintain the fractures open as pressure depletes in the well.